1. Field of the Invention
In general, this invention pertains to an apparatus which serves to reduce vehicle speed by inducing drag. More specifically, it relates to a disintegratable aerodynamic brake which generally retards speed of a vehicle re-entering the earth's atmosphere.
2. Description of the Prior Art
Heretofore, drag flaps attached to wing assemblies of subsonic aerodynamic vehicles have induced drag for purposes of reducing vehicle speed. An example of such type of drag flap is described in U.S. Pat. No. 2,418,273. With the advent of modern airborne vehicles re-entering the earth's atmosphere at velocities in excess of ten thousand miles per hour, in order to keep the vehicle itself at as low a maximum temperature as possible, it becomes advisable to construct drag flaps which would significantly reduce such velocities during re-entry while at the same time maintain vehicle maneuverability. However, conventional subsonic flap constructions are incapable of performing in the intended manner whenever subject to the intense temperature and pressure conditions encountered during re-entry.
Efforts have been made to provide supersonic vehicles with suitable drag inducing devices which are capable of providing suitable speed reductions when returning from a near space type environment. Illustrative of this kind of drag flap is one described in U.S. Pat. No. 3,067,971. The disclosed drag flap construction, while reducing vehicle velocity during descent from high altitudes and enabling satisfactory maneuverability of vehicle, is, however, incapable of successfully controlling the significant temperature increases from affecting the vehicle. Control of such extremely high temperatures is an important consideration for re-entry vehicles, especially if the vehicle is manned, such as a space shuttle. Aside from the foregoing significant drawback, drag flaps of the above-noted category which experience the noted extreme conditions during re-entry into the atmosphere from space may be unreliable for repeated use because of heat damage or induced stresses and strains. In this regard, after each re-entry they would have to be inspected to determine their structural integrity. Such inspection and maintenance would be costly. Further, conventional drag flaps might not be entirely reliable, particularly after repeated use. It should be noted that the reusability of a spacecraft and its components after re-entry has become a significant subject in view of the proposed use of space shuttles which would repeatedly enter the earth's atmosphere.
It will, therefore, be appreciated that conventional drag flap constructions for supersonic airborne vehicles are not effective, economical, or reliable for use on re-entry vehicles.